From 86191c3c09e7304818f54aef2ba48a13b06b049e Mon Sep 17 00:00:00 2001
From: Max Regan <mgregan2@gmail.com>
Date: Mon, 9 Jul 2018 02:19:39 +0000
Subject: [PATCH] cpu: remove some double-calls of mem_read()

For a veeery small performance benefit.
---
 src/gbemu/cpu.c | 118 ++++++++++++++++++++++++++----------------------
 1 file changed, 63 insertions(+), 55 deletions(-)

diff --git a/src/gbemu/cpu.c b/src/gbemu/cpu.c
index 65731c8..0040fca 100644
--- a/src/gbemu/cpu.c
+++ b/src/gbemu/cpu.c
@@ -153,79 +153,87 @@ static const unsigned int cb_extra_cycles[256] = { 0 };
 	} while (0)
 
 #define ADD_8(cpu, dst, src)						\
-	do {								\
-		(cpu)->nf = 0;						\
-		(cpu)->hf = CALC_H_ADD((src), (dst));			\
-		(cpu)->cf = CALC_C_ADD_8((src), (dst));			\
-		(dst) += (src);						\
-		(cpu)->zf = (dst) == 0;					\
+	do {											\
+		uint8_t _reg = src;							\
+		(cpu)->nf = 0;								\
+		(cpu)->hf = CALC_H_ADD((_reg), (dst));		\
+		(cpu)->cf = CALC_C_ADD_8((_reg), (dst));	\
+		(dst) += (_reg);							\
+		(cpu)->zf = (dst) == 0;						\
 	} while (0)
 
-#define ADD_16(cpu, dst, src)					\
-	do {							\
-		(cpu)->nf = 0;					\
-		(cpu)->hf = CALC_H_ADD((dst), (src));		\
-		(cpu)->cf = CALC_C_ADD_16((dst), (src));		\
-		(dst) += (src);					\
-	} while (0)						\
+#define ADD_16(cpu, dst, src)						\
+	do {											\
+		uint8_t _reg = src;							\
+		(cpu)->nf = 0;								\
+		(cpu)->hf = CALC_H_ADD((dst), (_reg));		\
+		(cpu)->cf = CALC_C_ADD_16((dst), (_reg));	\
+		(dst) += (_reg);							\
+	} while (0)										\
 
-#define ADC_8(cpu, dst, src)						\
-	do {								\
+#define ADC_8(cpu, dst, src)					\
+	do {										\
 		/* FIXME flag generation */				\
-		int tmp;						\
-		tmp = src + dst + cpu->cf;				\
-		cpu->nf = 0;						\
-		cpu->hf = CALC_H_ADD((src), (dst));			\
-		(dst) = tmp;						\
+		int tmp;								\
+		uint8_t _reg = src;						\
+		tmp = _reg + dst + cpu->cf;				\
+		cpu->nf = 0;							\
+		cpu->hf = CALC_H_ADD((_reg), (dst));	\
+		(dst) = tmp;							\
 		cpu->zf = (dst) == 0;					\
 	} while (0)
 
-#define SUB_8(cpu, dst, src)						\
-	do {								\
-		int tmp;						\
-		tmp = dst - src;					\
-		cpu->nf = 1;						\
-		cpu->hf = CALC_H_SUB(src, dst);				\
-		dst = tmp;						\
+#define SUB_8(cpu, dst, src)					\
+	do {										\
+		uint8_t _reg = src;						\
+		int tmp;								\
+		tmp = dst - _reg;						\
+		cpu->nf = 1;							\
+		cpu->hf = CALC_H_SUB(_reg, dst);		\
+		dst = tmp;								\
 		cpu->zf = (dst) == 0;					\
 	} while (0)
 
-#define SBC_8(cpu, dst, src)						\
-	do {								\
+#define SBC_8(cpu, dst, src)					\
+	do {										\
 		/* FIXME flag generation */				\
-		int tmp;						\
-		tmp = (dst) - (src) - 1;				\
-		(cpu)->nf = 1;						\
-		(cpu)->hf = CALC_H_ADD(src, dst);			\
-		(dst) = (tmp);						\
+		int tmp;								\
+		uint8_t _reg = src;						\
+		tmp = (dst) - (_reg) - 1;				\
+		(cpu)->nf = 1;							\
+		(cpu)->hf = CALC_H_ADD(_reg, dst);		\
+		(dst) = (tmp);							\
 		cpu->zf = (dst) == 0;					\
 	} while (0)
 
-#define AND_8(cpu, dst, src)			\
-	do {					\
-		(cpu)->nf = 0;			\
-		(cpu)->hf = 1;			\
-		(cpu)->cf = 0;			\
-		(dst) &= (src);			\
-		(cpu)->zf = ((dst) == 0);	\
+#define AND_8(cpu, dst, src)					\
+	do {										\
+		uint8_t _reg = src;						\
+		(cpu)->nf = 0;							\
+		(cpu)->hf = 1;							\
+		(cpu)->cf = 0;							\
+		(dst) &= (_reg);						\
+		(cpu)->zf = ((dst) == 0);				\
 	} while (0)
 
-#define XOR_8(cpu, dst, src)			\
-	do {					\
-		(cpu)->nf = 0;			\
-		(cpu)->hf = 0;			\
-		(cpu)->cf = 0;			\
-		(dst) ^= (src);			\
-		(cpu)->zf = ((dst) == 0);	\
+#define XOR_8(cpu, dst, src)					\
+	do {										\
+		uint8_t _reg = src;						\
+		(cpu)->nf = 0;							\
+		(cpu)->hf = 0;							\
+		(cpu)->cf = 0;							\
+		(dst) ^= (_reg);						\
+		(cpu)->zf = ((dst) == 0);				\
 	} while (0)
 
-#define OR_8(cpu, dst, src)			\
-	do {					\
-		(cpu)->nf = 0;			\
-		(cpu)->hf = 0;			\
-		(cpu)->cf = 0;			\
-		(dst) |= (src);			\
-		(cpu)->zf = ((dst) == 0);	\
+#define OR_8(cpu, dst, src)						\
+	do {										\
+		uint8_t _reg = src;						\
+		(cpu)->nf = 0;							\
+		(cpu)->hf = 0;							\
+		(cpu)->cf = 0;							\
+		(dst) |= (_reg);						\
+		(cpu)->zf = ((dst) == 0);				\
 	} while (0)
 
 #define CP_8(cpu, dst, src)				\